Kirgan has been many things in his life. He has tried to be a prospector, an inventor, a shopkeeper, an innkeeper and more. Kirgan eventually settled with miner, due to the simplicity of the job and good reward.

One day while mining, Kirgan found a stone tablet shattered in several pieces which featured a lot of ancient text he has not been able to translate. While pondering the connection of this and the vault door riddle, Kirgan met with Shadd, an archeologist. The two teamed up in an effort to locate ancient secrets. They journeyed to Ga-Koro where they were recruited into the Xa-Koro expedition team. The expedition took very long to start though, so Kirgan returned to Onu-Koro. There he met Hile and joined him on a brief adventure involving the stone tablet he had found, only to find out that it had no significance.

Much later, Kirgan was given a well-deserved holiday from mining. Bored, he ventured to Ta-Koro to look for Hile, but found Ril, who enlisted him temporarily in the Ta-Koro Guard. Kirgan helped Ril bust a drug dealing gang and returned to Onu-Koro to join an Ussal race.

One day while on his way to train for the race, Kirgan ran into a new Toa of Gravity named Vesun, who was having a dangerous case of spreading amnesia. Kirgan took him to the hospital, where they found out that only someone with telepathic abilities would be able to cure Vesun.

Vesun sent Kirgan to gather more information on the matter. While looking around, Kirgan met Khervos, who agreed to help him find a cure for Vesun's state. The two were on their way to Vesun, when they were ambushed by Kavala who was using the Shadowstone to cover them in darkness. Kavala kidnapped Kirgan and took him to a cave, which turned out to be Onoraza's hideout. Onoraza herself arrived and confronted Kavala, but the two agreed on a pact. While Kavala left to look for Khervos, Onoraza stood in her cave to guard Kirgan.

Kirgan was taunted by Onoraza until Khervos and Vesun arrived to save him. However, as the two stepped into the cavern, Kavala ambushed the group again, sealing them inside the cave. Kirgan began figuring out ways to get out, using his knowledge and experience in digging. The group broke out and were led back to Onu-Koro by Onoraza. They soon found Kavala and subdued him, taking his Shadowstone from him.

Kirgan joined Khervos to go to Ferron's Forge to tell Ferron and Tuli of Kavala's return. Tuli joined them and together they went back to Vesun to join him on a journey to Ko-Koro to find a telepath. However, the tunnel to Ko-Wahi had collapsed and the Cable Car was under the control of The Outsiders, who warned them about the dire situation in Ko-Koro.

The group decided to go to Le-Koro next, only to find it closed and abandoned due to the Entropy Beetle infestation. This led them to seek out help in Ga-Koro, where they met up with several beings in The Great Takea. Hearing that a Toa named Vakua might be able to help Vesun, the group set out to find him. However, on the way, Skorm left and sought out the Toa Kalta, Vakua being part of that group, and attacked them, beginning a large scale battle.

During the battle, Vesun overused his powers in order to save a falling Toa, and collapsed from the strain. Kirgan helped carry him into Juho's hut, where he kept him safe and tried to revive him.

Kirgan is peaceful by nature, but not ignorant to the reality of violence in his world. He is ready to fight for Onu-Koro at any time if the call comes, but until then remains tolerant to others, because he thinks it will make a change for the better. Kirgan is not a very adventurous person, but is still curious at heart and yearns for knowledge.

Kirgan's greatest weakness is his blind trust. He tends to be naïve and will rarely suspect that someone he trusts may be lying. He also gives up easily and does not like arguing with others. He can sometimes be socially akward and takes his time to get to know others before opening up to them. Due to being an Onu-Matoran, Kirgan has the natural ability to see well in the dark and is talented at digging. Bright light is especially hard on his eyes.